The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.
1. Field Of The Invention
The present invention pertains to mechanisms to decouple a warhead from a rocket motor to improve the precision of the rocket motor and more particularly to a bearing system to decouple a warhead from a rocket motor.
2. Description Of The Related Art
The precision of current rocket motors relates directly to the spin rate that they are capable of obtaining during use. When the spin rate is increased, this improves the precision of the rocket motor. In certain rocket motor systems, flutes are machined in the rocket nozzle body in order to generate torque, which, in turn, generates spin of the rocket motor during use. For example, flutes within a typical 2.75 inch rocket motor can generate a maximum of approximately 3 ft-lbs of torque. The spin rate that is generated from this torque relates directly to the weight of the warhead/rocket motor system.
One method that has been employed to reduce the weight of rocket motor portion of the system in order to increase the spin rate of the rocket motor, is to decouple the warhead from the rocket motor during use so the warhead spins separately from the rocket motor. Therefore, the same torque as discussed above can be applied to only the rocket motor, which weighs significantly less without the warhead attached, thus creating a higher spin rate. Many larger warhead/rocket motor systems use ball bearing systems to decouple the warhead from the rocket motor. However, in order to meet the precision requirements for military applications, such a ball bearing must be custom made. Also, because ball bearings require liquid lubrication in order to operate effectively, in order to maintain the systems over a long shelf life, regular service is required for such systems. Thus, for smaller warhead/rocket motor systems, it is not cost effective to employ such a decoupling system.
Therefore, it is desired to provide a low-cost system to decouple a warhead from a rocket motor during use for smaller warhead/rocket motor systems.
The present invention comprises annular bearings that allow a warhead to decouple from a rocket motor during use to increase the spin rate of the rocket motor, and, in turn, increase the precision of the rocket motor. The present invention is designed to be a low-cost, maintenance free alternative to ball bearing decouplers.
Accordingly, it is an object of this invention to provide a low-cost alternative to ball bearing decouplers for rocket motor and warhead systems.
It is a further object of this invention to provide a maintenance free bearing decoupler for rocket motor and warhead systems.
A still further object of this invention is to provide a more precise rocket motor and warhead system.
This invention accomplishes these objectives and other needs related to rocket motor and warhead systems by providing an improved precision rocket motor and warhead system by increasing the spin rate of the rocket motor. The system comprises a rocket motor tube with an outer housing segment attached to one end. An annular sleeve placed within the outer housing segment so that the end of the sleeve is aligned with the end of the outer housing segment. At least two annular bearings are placed around the outer surface of the sleeve. Normally the annular bearings will be made of a plastic type material that can be xe2x80x9cstretchedxe2x80x9d around the outside of the sleeve prior to placing it within the outer housing segment. The inner surface of the sleeve will include a warhead attachment mechanism to secure the warhead to the inner surface. Finally, the invention includes a locking mechanism that locks the sleeve in place within the outer housing segment while attaching the warhead to the sleeve and unlocks to allow the sleeve to rotate independently of the rocket motor tube.